Germany-based captive power solutions company Cronimet Mining Power Solutions (CRMPS) has built the first solar-diesel-hybrid power plant in the MW-scale at its subsidiary, Cronimet Chrome SA’s Thabazimbi chromium mine in South Africa.

In photovoltaic (PV)-diesel-hybrid power plants diesel consumption is reduced through the integration of a PV power plant. In comparison to traditional grid-connected PV power plants the engineering requirements are much higher.

The study “Solar, energy efficiency and load shifting for an optimized energy management in the mining industry” conducted by CRMPS and energy consultancy THEnergy shows the importance of considering both, demand side and supply side simultaneously.

The study is based on 26 interviews with experts from the mining and energy industries. The experts are from Africa, Australia and Europe.

Substantial electricity and cost savings

Typical cost savings from the PV side are in the range of 25%-30%, while in very remote locations with elevated diesel prices the reductions can amount to more than 70%.

The study reveals that on the demand side, energy efficiency measures and load shifting can have substantial effects on the electricity consumption of a mine.

Energy efficiency measures can be applied all along the mining value chain as well as for auxiliary applications. The main fields include compressed air systems, ventilation, material handling, pumping, crushing and milling.

Energy efficiency measures and load shifting schemes have a direct influence on the optimal design of the PV plant, while avoided or shifted energy consumption allows for designing the PV plant in an optimal way.

Often the integrated solution decreases the amount of capital expenditure needed for upgrading existing diesel generators with solar power considerably.

Energy efficiency measures and load shifting require a thorough knowledge of mining processes. It is obvious that the simultaneous optimisation of demand and supply side are much more complex than the construction of a traditional PV power plant. A prerequisite for finding the best solution is combining skills from both worlds, from mining and solar energy.

In addition, many of the solutions are novel with many improvements having been developed during the operation of PV-diesel-hybrid power plants at mining sites. A track record of on-site testing helps to implement new solutions in the most efficient way.